Abstract: A projection television lens system having a device that distorts for telescopically adjusting an A/B assembly, the tubular member that carries the A and B lens elements within a focus mount of a projection television lens system. Additionally, at one end of the lens, there is provided a fixed mounting site, i.e. a mounting site which is fixed in position with respect to the CRT 9 assembly. A device is then provided which connects the fixed mounting site to the tubular member. The thermal and structural characteristics of the device are selected so that the device itself distorts in response to temperature changes and thereby moves the A and B lens elements toward or away from the C element in response to, respectively, increased or decreased ambient temperature. In the most preferred embodiment, the fixed mounting site is on the focus mount at the image side of the lens assembly.